Pliers are known from German patent number 21 49 167. The pliers include a C-shaped pliers head having a plate arrangement with two plane cover plates. A stationary crimping die and a movable crimping die are arranged inside a circumferentially opened recess being located in the pliers head. The movable crimping die is linearly guided in an elongated slot being located in each of the cover plates by a guiding element. Two spaced apart guiding pins together with the elongated slot define a line of movement in which the stroke-like movement of the movable crimping die with respect to the pliers head occurs. A toggle lever drive is provided to linearly drive the movable crimping die. The toggle lever drive includes a handle being fixedly connected to the pliers head, a handle being pivotable with respect to the pliers head, the pivotable handle being pivotally connected to the guiding pin located in the guiding element facing the handles and to the toggle lever element, and a toggle lever element which is supported on a bearing being arranged at the cover plates in the line of movement. The guiding element and the toggle lever element are arranged one behind the other in the line of movement, so that the pliers head is comparatively long in this direction. The guiding pins are spaced apart from each other with a distance which is essential for the preciseness and for the tilt resistance of the linear guidance of the movable crimping die, and consequently for the quality of the crimped workpiece. The handles are made of metal and they are covered with handle-like coatings, the coatings covering a major portion of the handle extending from the pliers head. In the opened position of the pliers, the handles and the coatings, respectively, define the distance to be grabbed, meaning the distance to be grabbed at the beginning of the actuation of the pliers by the use of the thumb and the index finger. The ratio of transmission has to be considered since it has to be chosen great enough by realizing a specific construction to attain a great crimping force. The crimping dies of the pliers may include two alternatively usable nests which, for example, may have dimensions corresponding to workpieces of two different diameters.
Crimping pliers for crimping electrical conductors to corresponding connectors are known from U.S. Pat. No. 3,029,670. The pliers include a circumferentially opened recess being located in a C-shaped pliers head in which a first stationary crimping die is arranged, and in which a second crimping die is movably arranged. The movable crimping die is linearly guided in the pliers head by a cylinder-like guiding element. A toggle lever drive is provided for the stroke of the guiding element. The toggle lever drive is actuated by two handles, and it includes different additional levers. One of the levers of the toggle lever drive is supported in a stationary bearing. The disclosed pliers have a comparatively great overall length. The overall length of the pliers is determined by the need of room required for the linear guidance of the crimping die, and also by the arrangement of the toggle lever drive.
Other pliers for crimping workpieces are known from the European patent application number 0 203 241 A1. The pliers include a C-shaped pliers head, a stationary crimping die and a movable crimping die being arranged inside the pliers head. The movable crimping die is linearly guided inside the pliers head by a guiding element. The pliers head includes two longitudinal bores which are arranged symmetrically with respect to a longitudinal center plane. Two guiding projections being formed by a pin engage the two longitudinal bores. The pliers include a stationary handle and a pivotable handle. The pivotable handle is supported on the guiding projection facing the crimping dies. The guiding element has another longitudinal bore working together with a pin which is fixedly connected to the pliers head to form a linear guidance of the guiding element. The longitudinal bore determines the length of the possible stroke of the movable crimping dies and of the guiding element, respectively. The toggle lever drive is pivotally supported on the stationary pin by a toggle lever element. Thus, the stationary pin fulfils a guiding function for the guiding element as well as a supporting function for the toggle lever element of the toggle lever drive. The distance between these two guiding points depends on the angle of actuation of the handle. The pliers include only one nest being located at their crimping dies, so that tilt moments do not occur for the guiding element. The linearity of the guidance of the guiding element in the guiding point facing the crimping dies is only realized to a limited extend.